There are many patients susceptible to heart arrhythmias who are at risk of sudden death. For example, patients experiencing a coronary artery occlusion and myocardial infarction are at substantial risk of tachyarrhythmia for several weeks following the coronary artery occlusion. Such patients are generally hospitalized but can be discharged earlier if there is a practical means to protect them from life threatening arrhythmias. One such practical means includes the implantation of an automatic defibrillator. However, patients may also be discharged prior to such an implantation if an external defibrillator, such as, for example, a wearable defibrillator, is available in case they experience a life-threatening tachyarrhythmia.
There are also patients who are placed at an inordinate risk due to the surgery required for implanting an implantable defibrillator. For such patients, implantation would preferably be avoided so such an inordinate risk could be avoided or otherwise mitigated.
Wearable defibrillators are often used to help people with heart conditions that make them susceptible to life threatening cardiac arrhythmias. Such wearable defibrillators are typically configured to quickly treat a life threatening cardiac arrhythmia that is detected while a patient is wearing the device. For example, U.S. Pat. Nos. 4,928,690, 5,078,134, 5,741,306, 5,944,669, 6,065,154, 6,097,987, 6,253,099, 6,280,461 and 6,681,003, disclose wearable defibrillators. The entirety of U.S. Pat. Nos. 4,928,690, 5,078,134, 5,741,306, 5,944,669, 6,065,154, 6,097,987, 6,253,099, 6,280,461 and 6,681,003, are hereby incorporated herein by reference.
Wearable defibrillators are typically used to help patients that either cannot risk an implantation of a defibrillator or are awaiting such an implantation. Occasionally, a patient wearing a wearable defibrillator may appear to be experiencing a life threatening cardiac arrhythmia, but is not having such an event. In such circumstances, the wearable defibrillator is often configured to generate an audible alarm that is designed to stop if a patient provides a required response, such as, for example, pressing one or more response buttons. If a patient fails to press such buttons or otherwise provide a required response, the device may be configured to determine that the patient is unconscious and is undergoing a condition requiring treatment.
Occasionally, a passerby or bystander may interfere with the device by intentionally pressing the response buttons or otherwise providing a response to the wearable device causing the device to withhold treatment to a patient. Such interference can have tragic consequences because it may delay treatment a patient may need. For example, such interference may harm the patient by improperly delaying treatment and, in some cases, may result in patient death.
There is a need for wearable defibrillators and other medical devices to verify that a user providing a response is the patient and not a bystander by preventing anyone except the patient from responding when the patient is undergoing an event that could require treatment. Such verification preferably occurs during episodes of treatable cardiac arrhythmias.
The present invention is directed towards overcoming one or more of the above-mentioned problems.